1. Field of the Invention
The present invention relates to computer memory and more specifically to non-volatile memory.
2. Description of the Related Art
Memory can either be classified as volatile or nonvolatile. Volatile memory is memory that loses its contents when the power is turned off. In contrast, non-volatile memory does not require a continuous power supply to retain information.
The invention of non-volatile memory called “Flash” memory provided large capacity memory and reasonable write speeds. With flash it became possible to make systems using controllers and memory together to make flash memory systems that operate as mass storage for applications requiring low power and high ruggedness. Flash memory became popular because it is noiseless, has faster access than a hard disk, is smaller in size than a hard disk, and has no moving parts so it is more rugged than a hard disk. After the popularity of this card succeeded, many other versions of card were developed. Some conventional uses of Flash memory include: an additional disk drive for personal computers (PCs) and for portable equipment, personal portable electronic devices such as cell phones, PDA's, music players, etc., computer basic input/output systems (BIOS) chips, digital cameras, and memory cards for game consoles.
As electronic systems advance in capability and functions, the demand for higher memory capacity devices increases. This demand has pushed the development of ever increasing memory densities and of stacking of memory devices to obtain a high density. However, these solutions are often expensive. Thus, even with all the efforts to date, obtaining high capacity memory at a low cost point has eluded the market.
Conventionally, Flash memory is more expensive and has a lower capacity than a hard disk drive. Another problem associated with these cards is the write speed. Many applications require access speeds that are not possible with the existing technology. This often requires the system to buffer large blocks of data in dynamic random access memory (DRAM) or in static random access memory (SRAM), driving up system cost.
Continuing efforts are being made to improve memory systems.